The overarching objective of this study is to increase understanding of the role of maternal smoking during pregnancy on intergenerational transmission of smoking. The study employs data on mother's smoking trajectories prior to pregnancy, during pregnancy and after birth in combination with data on the smoking trajectories of children during pre-teenage years, adolescence, and young adulthood (e.g., smoking experimentation, progression to daily use, and respective patterns of discontinuation and/or relapse) to examine the direct, indirect, and concurrent effects of mother's smoking trajectories on children's smoking trajectories. Employing social and developmental theory about in utero exposures, gene-environment interactions, social stratification, and acculturation, the study defines and evaluates hypotheses about the direct, indirect, and concurrent effects of mother's smoking on her children's smoking trajectories. The supplement exploits paradoxes in the observed patterns of difference by race/ethnicity and by immigrant generation (mother foreign-born versus mother native-born) in prevalence and trajectories of maternal smoking trajectories and youth smoking trajectories to provide additional tests of hypotheses about direct and indirect effects of maternal smoking during pregnancy on children's smoking trajectories. The methodological approach extends findings from an ongoing NICHD (R03) research project. Data come from a population-representative cohort of mothers in the National Longitudinal Survey of Youth 1979 (NLSY79) and an ongoing biennial survey of all children born to these women since 1986, i.e., the Children and Young Adults of the NLSY79 (NLSY79-CYA). These data are well suited to the project aims in light of the oversample of Hispanic, black, and socioeconomically disadvantaged white mothers. Together the NLSY79 and NLSY79-CYA offer a rich source of intergenerational data on maternal and youth substance use, child cognitive and behavioral development, and the social and biological determinants of tobacco use at the child, family, peer, and neighborhood level. The investigators employ an autoregressive latent trajectory approach that allows them to examine causal relationships among determinants measured at different ages, while also using latent variable methods to correct for the underestimation of mediation through social and developmental pathways. Findings will provide evidence strengthening the understanding of intergenerational social and biological mechanisms whereby children accumulate vulnerability and resilience to different smoking trajectories from exposures in utero through young adulthood. PUBLIC HEALTH RELEVANCE: This study examines how intergenerational pathways in early life, childhood, and adolescence shape tobacco-related determinants of the health and social well-being of maturing adolescents and young adults, with specific attention to differences in the mechanisms linking mother's smoking to youth's smoking by race/ethnicity, immigrant generation, and gender.